Dual event slotted paging

ABSTRACT

A novel and improved method and system for paging a cellular telephone or other wireless terminal using two paging channels that reduces standby mode power consumption described. In one embodiment of the invention, a minimally encoded quick paging channel is established over which short, quick page messages are transmitted during one of a set of quick paging slots. The quick page message indicates that a communications request has been received, and that the receiving communication terminals should process a highly encoded full paging channel over which more detailed, full page messages are transmitted during the next full paging slot. A terminal monitors full paging channel only after a quick page message has been received on the quick paging channel.

CLAIM OF PRIORITY UNDER 35 U.S.C. §120

The present Application for Patent is a Continuation and claims priorityto U.S. patent application Ser. No. 10/981,359 entitled “Dual EventSlotted Paging” filed Nov. 3, 2004, now pending, which is a Continuationof U.S. patent application Ser. No. 10/062,209 entitled “Dual EventSlotted Paging” filed Jan. 31, 2002, now U.S. Pat. No. 6,832,094, whichis a continuation of U.S. patent application Ser. No. 08/890,355entitled “Dual Channel Slotted Paging” filed Jul. 9, 1997, now U.S. Pat.No. 6,393,295, which is a Continuation-in-Part of U.S. patentapplication Ser. No. 08/865,650 entitled “Dual Channel Slotted Paging”filed May 30, 1997, now U.S. Pat. No. 6,111,865, all of which areassigned to the assignee of the present application hereof and herebyexpressly incorporated by reference herein.

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention relates to wireless telecommunications. Moreparticularly, the present invention relates to a novel and improvedmethod and apparatus for paging a cellular telephone or other wirelesscommunications device.

II. Description of the Related Art

The IS-95 cellular telephone standard (and its derivatives such asIS-95A and ANSI J-STD-008 referred to herein collectively as IS-95) usesadvanced signal processing techniques to provide efficient and highquality cellular telephone service. For example, an IS-95 compliantcellular telephone system utilizes vocoding, error detection, forwarderror correction (FEC), interleaving and spread spectrum modulation inorder to make more efficient use of the available RF bandwidth, and toprovide more robust connections. In general, the benefits provided byIS-95 include longer talk time, higher capacity, and fewer dropped callswhen compared to other types of cellular telephone systems.

To conduct communications in an orderly manner, IS-95 provides a set ofhighly encoded channels over which data having different functions istransmitted. These highly encoded channels include a paging channel overwhich paging messages are transmitted notifying cellular telephones orother types of wireless terminals that an incoming request tocommunicate is pending. In accordance with the IS-95 standard, pagingmessages are transmitted at low to medium data rates (4800 or 9600 bps)during time slots that are preassigned to groups of cellular telephones.Table I provides the data included in a General Page Message as anexample of typical a paging message generated substantially inaccordance with the IS-95A standard.

TABLE I Message Field Length (Bits) MSG_TYPE (Message Type) 8CONFIG_MSG_SEQ 6 ACC_MSG_SEQ 6 CLASS_0_DONE 1 CLASS_1_DONE 1 RESERVED 2BROADCAST_DONE 1 RESERVED 4 ADD_LENGTH 3 ADD_PFIELD 8× ADD_LENGTH Andzero or more occurrences of the following page record: PAGE_CLASS 2PAGE_SUBCLASS 2 Page class specific fields Typically 2–12 bytes.

Table I is provided simply to illustrate the length of a typical pagingmessage, so a detailed description of the function of each field is notincluded herein. Such a detailed description may obtained, however, byreferring to the well known, and publicly available, IS-95 standard (inparticular the IS-95A standard). The paging messages also begin with aneight bit message length field (MSG_LEN), that indicates the length ofthe message, and end with a 30 bit cyclical-redundancy-check (CRC) field(not shown).

To monitor for paging messages, a cellular telephone periodicallymonitors the paging channel during the assigned paging slot. Inparticular, the cellular telephone periodically activates complex RF anddigital signal processing circuitry for as long as is necessary tosuccessfully process the paging message. Since the typical pagingmessage is relatively long, and transmitted via a highly encoded low tomedium rate channel, the associated processing during each paging slotrequires a significant amount time and signal processing resources, andtherefore requires a significant amount of power to complete. Thisreduces the amount of time an IS-95 cellular telephone can remain instandby mode using a battery of given capacity, and therefore is highlyundesirable.

SUMMARY OF THE INVENTION

The present invention is a novel and improved method and system forpaging a cellular telephone or other wireless terminal that reducesstandby mode power consumption. In accordance with one embodiment of theinvention, a minimally encoded quick paging channel is established overwhich short, quick page messages are transmitted during one of a set ofquick paging slots. The quick page message indicates that a request tocommunicate has been received and that the receiving communicationterminals should process a highly encoded full paging channeltransmitted during the next full paging slot for a more detailed, fullpage message. A communications terminal monitors full paging channelafter a quick page message has been received on the quick pagingchannel.

To page the communications terminal, a base station controller firstgenerates the quick page message during a quick page slot assigned to aset of communications terminal that includes the particularcommunications terminals being paged. This is followed by a full pagemessage identifying the particular communications terminal. Thecommunications terminal periodically monitors the quick paging slot and,upon detecting the quick page, activates decoding circuitry forprocessing the full paging channel. Upon processing the full pagingchannel, the communications terminal determines if the full page messageis directed to it, and if not, deactivates the decoding circuitry andreturns to processing the quick paging channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, objects, and advantages of the present invention willbecome more apparent from the detailed description set forth below whentaken in conjunction with the drawings in which like referencecharacters identify correspondingly throughout and wherein:

FIG. 1 is a block diagram of a cellular telephone system;

FIG. 2 is a timing diagram illustrating the timing slots in the quickpaging channel and the full paging channel;

FIG. 3 is a flow diagram illustrating the steps performed during thepaging of a wireless terminal;

FIG. 4 is a block diagram illustrating the coding performed on the fullpaging channel and the quick paging channel;

FIG. 5 is a flow diagram illustrating the steps performed by a wirelessterminal during standby mode; and

FIG. 6 is a block diagram of a receiver configured in accordance withone embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method and system for paging a cellular telephone or other wirelessterminal that reduces standby mode power consumption is described. Inthe following description the invention is set forth in the context of acellular telephone system operating substantially in accordance with theIS-95 standard. While the invention is particularly suited for operationin such an environment, many other digital communication systems canbenefit from the use of the present invention, including TDMA basedwireless communication systems, satellite based communication system,and wireline systems over which encoded signaling is transmitted.

FIG. 1 is a block diagram of a highly simplified cellular telephonesystem configured in accordance with the use of the present invention.Wireless terminals 10 (typically cellular telephones) are located amongbase stations 12. Wireless terminals 10 a and 10 b are in active modeand therefore are interfacing with one or more base stations 12 usingradio frequency (RF) signals modulated in accordance with the CDMAsignal processing techniques of the IS-95 standard. A system and methodfor processing RF signals substantially in accordance with the use ofthe IS-95 standard is described in U.S. Pat. No. 5,103,459 entitled“System and Method for Generating Signal Waveforms in a CDMA CellularTelephone System” assigned to the assignee of the present invention andincorporated herein by reference ('459 patent). The other wirelessterminals 10 are in standby mode and therefore monitoring for pagemessages indicating a request to communicate.

In the preferred embodiment of the invention, each base stationgenerates a forward link signals comprised of a set of forward linkchannels. The channels are established by a set of orthogonal 64 chip(or bit) Walsh codes, each of which is used to modulate the dataassociated with a particular channel. The channels are categorized byfunction and include a pilot channel over which a phase offset patternis repeatedly transmitted, a synch channel over which synchronizationdata is transmitted including the absolute system time and the phaseoffset of the associated pilot channel, and traffic channels over whichthe data directed to the terminals are transmitted. The traffic channelsare normally assigned to transmit data to a particular wireless terminal10 for the duration of the interface with that particular base station.

Additionally, in accordance with one embodiment of the invention, one ormore or the Walsh channels are designated as quick paging channels, andone or more or the Walsh channels as full paging channels. Thedesignation and operation of the full paging channels is preferablyperformed in accordance with the paging channel specified by the IS-95standard. Some methods and apparatus for performing paging substantiallyin accordance with the IS-95 standard are described in U.S. Pat. Nos.5,392,287 ('287 patent) entitled “APPARATUS AND METHOD FOR REDUCINGPOWER CONSUMPTION IN A MOBILE COMMUNICATIONS RECEIVER” AND U.S. Pat.Nos. 5,509,015 ('015 patent) entitled “METHOD AND APPARATUS FORSCHEDULING COMMUNICATIONS BETWEEN TRANSCEIVERS” both assigned to theassignee and incorporated herein by reference.

As described in the '287 and '015 patents, and as specified by the IS-95standard, the full paging channel is time divided into time “slots”. Theslots are, in turn, assigned to groups of wireless terminals, where theassignment is performed based on the International Mobile Subscriber ID(IMSI) which is unique for each wireless terminal 10, or other terminalidentification information such as one or more Mobile IdentificationNumbers (MIN). In alternative embodiments of the invention otheridentification information may also be used including the electronicserial number (ESN) of the wireless terminal or the temporary mobilesubscriber ID (TMSI). Others will recognize additional values that maybe used. The various possible types of identification information thatmay be used will be referred to hereinafter collectively as the MOBILEID. The quick paging channels are also divided into time slots.

FIG. 2 is a timing diagram illustrating the time slots of a full pagingchannel and a quick paging channel when configured in accordance withone embodiment of the invention. The quick paging channel is dividedinto quick paging slots 30 and the full paging channel is divided intofull paging slots 32 which are preferably longer in duration that thequick paging slots. Sets, or groups, of quick paging slots 30 areassigned to single full paging slots 32 as illustrated by the diagonalarrows, although the use of a one-to-one correspondence between quickpaging slots and full paging slots, or other ratios, is consistent withthe use of the invention. The assignment of the quick paging slots 30 toa particular set of wireless terminals is preferably performed viaapplication of a hashing function to the MOBILE ID of the wirelessterminal 10.

To page a particular wireless terminal 10, a quick page message istransmitted during the quick paging slot and a full page message istransmitted during the full page slot assigned to that wirelessterminal. The quick paging slot and full paging slots occur in aperiodically repeating fashion, which ensures that a slot associatedwith a particular terminal occurs after some limited period of time. Asillustrated in FIG. 2, the full page slots 32 occur a delay 34 after theassociated quick paging slots 30 to allow the wireless terminal toprocess the quick page message and activate additional decodingcircuitry before the next full page slot.

FIG. 3 is a block diagram of the steps performed by BSC 14 during thepaging process. The paging process begins at step 36 and at step 38 itis determined whether a request to communicate has been received. If notstep 38 is performed again.

If a request to communicate has been received, the full paging slot andquick paging slot associated with the wireless terminal to which thecommunication request is directed are calculated at step 40 based on theMOBILE ID or other identification information of that wireless terminal10. In one embodiment of the invention, the quick paging slot iscalculated using a first hashing function, and the full paging slot iscalculated using a second hashing function where the second hashingfunction is different than the first hashing function. Additionally, thefull paging slots are on the order of 80 ms, while the quick pagingslots are on the order of 5 ms. The wireless terminal 10 may have toprocess all or part of the full paging channel depending on the contentof the paging message being received in accordance with IS-95. BSC 14preferably performs the necessary processing using one or moremicroprocessors running software stored in memory (not shown).

In an exemplary embodiment of the invention, the full paging slot isdetermined in accordance with the above referenced '287 and '015patents, and the quick paging slot is determined by application ofanother hashing function to the MOBILE ID, although the use of othermethods for assigning paging slots to wireless terminals is consistentwith the use of the present invention. In particular, the full page slotcorresponds to the system time t, provided in frames of 20 ms, where thefollowing equation is true:(floor(t/4)−PGSLOT)mod(16*T)=0,  (1)where T is a slot cycle length in units of 1.28 second given by T=2^(i)where i is the slot cycle index (SCI). PGSLOT is determined using a thefollowing hashing function:PGSLOT=floor(N×((40505×(L≈H≈DECORR))mod 2^16)/2^16),  (2)where L is the 16 least significant bits of a 32-bit HASH_KEY and H is16 most significant bits of the HASH_KEY, and N is 2048. The HASH_KEY ispreferably the MOBILE_ID or some derivative thereof such and the IMSI.The function floor(x) returns the largest integer less than or equal tox. For example, the result of floor(2.99), floor(2.01) and floor(2.00)is 2 and the result of floor (−2.5) is −3. The decorrelation valueDLCORR is calculated as follows:DECORR=6×HASH₁₃ KEY[0 . . . 11]  (3)where HASH₁₃ KEY[0 . . . 11] is the eleven least significant bits of the32 bit HASH₁₃ KEY value.

The hashing function used to determine the quick paging slot in apreferred embodiment of the invention is calculated in a similar mannerto the full paging slot, except that the quick paging slot occursbetween 40 to 120 ms before the full paging slot, and the set ofwireless terminals assigned to a quick paging slot changes over time toensure that each wireless terminal 10 is associated with a different setof other wireless terminals 10 during each quick paging slot. Varyingthe set of terminals 10 with which each wireless terminal 10 isassociated during each paging slot helps ensure that less activewireless terminals do not become permanently associated with a moreactive wireless terminal 10, and therefore have to unnecessarily monitorfor a large number full paging messages that are not directed to it.

In an exemplary embodiment of the invention, the quick paging slot for awireless terminal 10 occurs within an 80 ms quick page period thatbegins 120 ms before the beginning of the full paging slot as calculatedby the following equation:(floor((t−6)/4)−PGSLOT)mod(16*T)=0,  (4)where PGSLOT is the same as that used for the full paging slot. Theduration of the quick page period is preferably 80 ms. The quick pageperiod is divided into quick paging slots during which the quick pagemessages are transmitted, which is described in greater detail below.Preferably, the quick paging slots and associated quick page messagesare a single bit in duration. Therefore, the number of quick pagingslots per quick page period is a function of the data rate of the quickpaging channel.

As should be apparent, equation (4) is the same as equation (1) exceptthat system time is offset by six frames, which causes the beginning ofthe quick page period to begin 120 ms before the full page slot.Providing an offset of 120 ms ensures that there is at least 40 ms oftime exists (given the quick page period of 80 ms) between anyparticular quick page slot and the full page slot, which gives thewireless terminal enough time to prepare to process the full pagemessage after receiving a quick page message.

Within the 80 ms quick page period, the quick paging slot (having aduration of one bit) assigned to a particular wireless terminal 10 isdetermined using the following equation:QUICK₁₃ PGSLOT=1+floor(N×((40505×(L≈H≈DECORR))mod 2^16)/2^16),  (5)with the value N is set to the quick paging channel data rate (QPAGE₁₃RATE) in number of bits per 80 ms slot. For example, if the quick pagingchannel data rate is 9600 bits/second the value QPAGE_RATE is equal to768 bits/frame. Additionally, the decorrelation value is set as follows:DECORR=floor((t−6)/64)mod 2^16.  (6)

Thus, equation (5) returns a value between 1 and 768 corresponding tothe quick paging slot (or bit location) within an 80 ms quick pageperiod that begins 120 ms before the corresponding full paging slot. Thewireless terminal monitors the quick paging channel during this quickpaging slot and if a quick page message is received, the wirelessterminal will then monitor the full paging channel for a full pagingmessage.

As should be apparent from equation (6), the decorelation value DECORRfor the quick paging channel is calculated as a function of system time,and therefore the resulting value QUICK_PGSLOT for a given set ofwireless terminals 10 will differ as time progresses. This causes theset of wireless terminals 10 associated with a particular full pagingslot to have different quick paging slots over time (although they maystill be paged during the same quick page period), which will helpensure that a less active wireless terminal 10 is not tied to a moreactive wireless terminal 10 which would cause it to monitor the fullpaging channel with unnecessary frequency, and therefore unnecessaryenergy consumption.

Once the quick paging slot and the full paging slot are determined, BSC14 transmits a quick page message at step 42 on a quick paging channel,and full page message at step 44 on a full paging channel, via one ormore base stations 12. The base stations 12 encode and modulate thepaging channels as described in greater detail below, and transmissionof the two page messages occurs during the corresponding quick pagingslot and full paging slot.

After transmission of the quick page message and the full page message,the BSC 14 polls for a response at step 46 indicating that the page wasreceived. If a response was received the communication begins at step50.

If no response was received after a time-out period, a second quick pagemessage is transmitted at step 52, and a second full page message istransmitted at step 54. At step 56 the BSC 14 polls for a response fromthe wireless terminal 10 and determines at step 58 if a response wasreceived. If a response was received, the communication begins at step50. If it is determined at step 58 that no response was received, thepage fails at step 60. In an alternative embodiment of the invention,two or more quick paging messages and two or more corresponding fullpage messages are generated for each page. The second quick page messageand full page message increase the likelihood of the page beingreceived, without introducing the delay necessary to determine whetheran acknowledgment message has been received from the wireless terminal10.

In the preferred embodiment of the invention, the quick page message iscomprised of an INCOMMING_PAGE bit. An INCOMMING_PAGE bit in a firststate (such as logic high) indicates that a communication request hasbeen receive for one of the wireless terminals 10 associated with thatquick paging slot, and therefore that those wireless terminals shouldprocess the full paging channel during the next designated full pagingslot. An INCOMMING_PAGE bit in a second state (such as logic low)indicates that no communication request has been received for thosewireless terminals 10, and therefore the full paging channel should notbe processed during next assigned full paging slot. Hence, the quickpage message is more highly encoded than the full page message, sincethe page is represented by a single bit, rather than a substantiallyhigher number of bits, and therefore can be processed with fewerresources. Such “message” encoding should not be confused with the“channel” coding described below, where a greater amount of encodingrequires more data processing resources, and therefore is less desirablein term of power consumption.

In the preferred embodiment of the invention, the full page messagecontains the information specified in the IS-95 standard for a normalpage message that allows each wireless terminal 10 to determine whetherthe page is directed to it. An example of a page generated in accordancewith the IS-95A standard in provided in Table I listed above. Asillustrated by Table I, the full page message contains significantlymore information than the quick page message, which is preferablycomprised of a single bit. Therefore, the quick page message can beprocessed more easily by each wireless terminal 10, and with less power,than a full page message.

In alternative embodiments of the invention, multi-bit quick pagemessages are used. These multi-bit quick paging messages are used toencode and convey additional information beyond simply indicating thatthe wireless terminal 10 should monitor the full paging channel duringthe next assigned full paging slot 32. For example, the multi-bit quickpage message could be used to indicate more particularly which wirelessterminal 10 is being paged from the subset of wireless terminal assignedto the corresponding quick page slot 30. The multi-bit quick pagemessage could also be used to indicate that the full paging channelshould be monitored for a longer duration so that system parameterchanges can be broadcast to all the wireless terminals 10. Those skilledin the art will recognize various useful types of information that canbe transmitted using a multi-bit quick page message. Also, in anotheralternative embodiment of the invention, reduced forward errorcorrection encoding is performed on the quick page message.

In addition to transmitting less information in a quick page messagethan in a full page message, the preferred embodiment of the inventionincorporates a minimal coding scheme for the quick paging channel whencompared to the full paging channel. FIG. 4 provides an illustration ofthe coding schemes employed for the full paging channel and the quickpaging channel in accordance with one embodiment of the invention.

As shown in FIG. 4, data transmitted via the full paging channel isconvolutionally encoded by convolutional encoder 60 and the resultingcode symbols repeated by symbol repeater 61 in order to generate symbolsat a predetermined rate. The repeated code symbols are then blockinterleaved by block interleaver 62. The data from block interleaver isscrambled via EXCLUSIVE-OR (XOR) with a decimated long code generated bylong code generator 64 and decimator 66. The long code is binary codegenerated in predetermined manner as a function of a seed number, and isknown to all wireless terminals 10. The scrambled data is the modulatedwith a Walsh channel code designated for a full paging channel, and theWalsh channel code modulated data is QPSK spread using a pseudorandomnoise code (PN code), summed with the data from the other channels, andupconverted for transmission, preferably in accordance with the IS-95standard (spreading, summing and upconversion not shown.)

Still referring to FIG. 4, data transmitted via the quick paging channelis applied directly to a Walsh channel code designated for a quickpaging channel, and then spread, summed and upconverted as describedabove. Preferably, a single bit of data transmitted via the quickchannel is modulated multiple times by the same Walsh code, effectivelytransmitting the bit multiple times. One could also transmit the databit repeatedly using a symbol repeater like symbol repeater 61 used forthe full paging channel. In still another embodiment of the invention,the quick paging channel could be scrambled using the long code asperformed for the full paging channel.

As should be apparent from FIG. 4, the processing associated withtransmitting information over the quick paging channel is substantiallyless in both duration and complexity than that associated with the fullpaging channel. Therefore, the amount of processing necessary to performreceive processing of the quick paging channel is also substantiallyless, and therefore requires less energy than that necessary for thefull paging channel. While the reduced amount of processing performedfor the quick paging channel does increase the likelihood of errorduring the processing of any particular bit, other methods for reducingthe effect of this increased error rate, without substantiallyincreasing complexity, can be employed. The methods include transmittingthe same bit multiple times or interpreting low quality transmissions aspositive page messages as described below.

FIG. 5 is a flow diagram of the processing performed by a wirelessterminal 10 in standby mode when performed in accordance with oneembodiment of the invention. The processing is preferably performedusing a microprocessor controller by software instructions stored inmemory coupled to other integrated circuits and systems that are wellknown in the art (not shown). The processing begins at step 80 and atstep 84 it is determined whether the assigned quick paging slot hasarrived, and if not step 82 is performed again.

If the assigned quick paging slot has arrived, the wireless terminal 10processes the quick paging channel at step 86. Preferably, theprocessing is performed using a significantly smaller subset of thesignal processing circuitry contained in the wireless terminal than usedto process full page messages. In accordance with the transmitprocessing performed for the quick paging channel shown in FIG. 4, thereceive processing is preferably comprised of downconversion of the RFenergy received, despreading with the PN spreading code, anddemodulation with the designated Walsh code. The resulting soft decisiondata is processed directly to determine the logic level transmitted.

Referring again to FIG. 5, at step 88 it is determined whether a quickpage message was received at step 86 based on the logic level of thedata detected. If a quick page message was detected processing continuesat step 90 as described below. If a quick page message was not detected,it is further determined at step 89 whether the signal quality duringthe processing of the quick paging channel was acceptable. If so, thewireless terminal 10 returns to step 82. If the signal quality was notacceptable, processing continues at step 90 as described below.

The received signal quality can be determined by various well knownmethods including determining when the receive power of the signal fromtransmitted from transmitter 50 falls below a threshold, or bydetermining when the signal-to-noise ratio of the pilot channel fallsbelow a predetermined threshold. By monitoring for a full page messagewhen the received signal quality is unacceptable, the number of missedfull page messages due to undetected quick page messages resulting fromunacceptable signal quality is minimized.

If a quick page message was detected, or the received signal quality wasnot acceptable, the wireless terminal 10 activates additional decodingcircuitry at step 90 and, at step 92 processes the full paging channelduring the assigned full paging slot using the activated circuitry. Thetime between the quick paging slot and the full paging slot assigned toa particular terminal must be sufficient to allow activation of theadditional decoding circuitry within the wireless terminal 10 afterdetection of the quick page message before the full page slot occurs.

At step 94, the wireless terminal 10 determines whether the full pagemessage processed at step 92 was directed to it based on the addresscontained in that message, and if not decoding circuitry within wirelessterminal 10 is deactivated at step 82 and step 84 is performed again. Ifthe full page message was directed to the wireless terminal 10,processing for the corresponding communication begins within thewireless terminal at step 96, and the wireless terminal enters activemode at step 98.

FIG. 6 is a block diagram providing a highly simplified illustration ofwireless terminal 10 when configured in accordance with one embodimentof the invention. Digital demodulator 302, block interleaver 304,trellis decoder 306 and control system 308 are coupled via a digitalbus, and RF receiver 300 is coupled to digital demodulator 302.

During standby mode, control system periodically activates RF receiver300 and digital demodulator 302 to process the pilot and quick pagingchannels. RF receiver 300 downconverts and digitizes RF signals anddigital demodulator 302 performs digital demodulation for a firstduration generating soft decision data for the channels being processed.Control system 308 examines the pilot channel soft decision data todetermine the quality of the signal and examines the quick pagingchannel to determine if a quick page message has been received.

If a quick page message has been received, or the signal has beenreceived with poor quality, control system 308 activates blockdeinterleaver 304 and trellis decoder 306 and configured digitaldemodulator to begin processing the full paging channel for a secondduration that is longer than the first duration. Control system 308 thenmonitors the data received over the full paging channel for a fullpaging message directed to it, and if none is detected, deactivatesblock deinterleaver 304 and trellis decoder 306 and continues in standbymode. If a full page message is detected, control system 308 placeswireless terminal in active mode during which the associatedcommunication is conducted.

In still another embodiment of the invention, the quick paging channeland the full paging channel are combined on to the same code channel.That is, the quick paging channel and the full paging channel aremodulated with the same Walsh code. Within the same code channel thequick paging channel and the full paging channel are logicallydistinguished by a predetermined time division scheme. For example,during some 80 ms slots quick paging messages are transmitted, whileduring other 80 ms slots full paging channel messages are transmitted inaccordance with a predetermined slot allocation scheme. Thisimplementation simplifies the receive and transmit processing somewhatby only requiring modulation and demodulation of a single code channel,but would require more significant modification to the existing IS-95standard and therefore provides less compatibility with existing IS-95compliant wireless communication systems.

As should be apparent from the description provided above, by pagingusing a quick page message with a minimal number of bits, and which istransmitted over a minimally encoded channel, the present inventionallows a wireless terminal to consume less power when monitoring forpage messages during standby mode. Consuming less power in standby modeallows a wireless terminal to operate longer on a given battery, andtherefore extends the standby time of that wireless terminal. Sincewireless terminals are typically used in mobile telecommunications, itis often necessary to go extended periods of time without recharging orreplacing the battery of the wireless terminal. Thus, in order toprovide increased convenience, and to reduce the likelihood of missingpage messages due to battery depletion, extending the standby time for agiven battery size is highly desirable.

Additionally, since quick page messages are transmitted within a highlyreduced period of time, monitoring for quick page message can beperformed during active mode when a phone call or other communication isbeing processed in addition to standby mode. Such monitoring can beperformed by briefly suspending processing of the traffic channel toallow processing of the quick paging channel during the quick pagingslot. Since the quick paging slot is on the order of 5 ms, any lost datawill typically not be missed or detected, and can often be recoveredusing the forward error correction (FEC) encoding. Once the quick pagemessage is received, the full paging message may be received by furthersuspending processing of the traffic channel by transmission of asignaling message to the base station controller, followed by processingof the full paging channel. Thus, the ability to receive paging messageduring active mode is enhanced by the use of the dual event pagingscheme described herein.

Thus, a dual channel method and system for paging cellular telephonesand other wireless terminals that reduces standby power consumption hasbeen described. The previous description of the preferred embodiments isprovided to enable any person skilled in the art to make or use thepresent invention. The various modifications to these embodiments willbe readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other embodiments withoutthe use of the inventive faculty. Thus, the present invention is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

1. A method for paging a wireless communication device in a wirelesstelecommunications system comprising: transmitting a quick page messagevia a first, less encoded channel, said quick page message notifying thewireless communication device to begin monitoring a second highlyencoded channel for a full page message; transmitting said full pagemessage via said second channel; wherein processing said second channelincludes encoding through a encoder, interleaving through aninterleaver, and adding cyclic redundancy check through a cyclicredundancy check circuit to said full page message, wherein said quickpage message contains less data bits than said full page message, suchthat the amount of processing to process said quick page message issubstantially less than for the full page message in the wirelesscommunication device; wherein said wireless communication device is aparticular wireless communication device included within a set ofwireless communication devices in said wireless communication system;wherein said set of wireless communication devices includes a pluralityof wireless communication devices; wherein said quick page message isfor directing said set of wireless communication devices to monitor saidsecond channel for said full page message; wherein said full pagemessage identifies said particular wireless communication device amongsaid set of wireless communication devices; wherein said transmittingsaid quick page message is during a first time slot assigned to the setof wireless communication devices; wherein said transmitting said fullpage message is during a second time slot assigned to the set ofwireless communication devices; wherein said second time slot isassigned to said first time slot by way of having a time delaycalculated by the wireless communication device between said first andsecond time slots; wherein said second time slot occurs after said firsttime slot.
 2. The method as set forth in claim 1 wherein said quick pagemessage is comprised of a single bit of data.
 3. The method as set forthin claim 1 wherein said first channel is established via direct sequencemodulation with a first channel code, and said second channel isestablished via direct sequence modulation with a second channel code.4. The method as set forth in claim 1 for paging a wirelesscommunication device further comprising the steps of generating a quickpage message before said step of transmitting said quick page messagevia a first channel; and generating a full page message beforetransmitting said full page message via said second channel.
 5. Themethod as set forth in claim 1 further comprising the steps of: directsequence spreading said full page message; and direct sequence spreadingsaid quick page message.
 6. The method as set forth in claim 1 furthercomprising the steps of: receiving said quick page message during saidfirst time slot; activating signal processing circuitry; and receivingsaid full page message during said second time slot and using saidactivated signal processing circuitry to process said full message. 7.The method as set forth in claim 6 wherein said signal processingcircuitry is comprised of a trellis decoding system.
 8. The method asset forth in claim 6 wherein said signal processing circuitry iscomprised of a deinterleaver.
 9. The method as set forth in claim 6wherein said signal processing circuitry is comprised of a cyclicalredundancy check circuit.
 10. A method for receiving a page at awireless communication device in a wireless telecommunications systemcomprising: receiving a quick page message via a first, less encodedchannel, said quick page message notifying the wireless communicationdevice to begin monitoring a second, highly encoded channel for a fullpage message; receiving said full page message via said second channel;wherein processing said received full page message includes decodingthrough a decoding system, deinterleaving through a deinterleaver, andprocessing through a cyclical redundancy check circuit; wherein saidquick page message contains less data bits than said full page message,such that the amount of processing to process said quick page message issubstantially less than for the full page message in the wirelesscommunication device; wherein said wireless communication device is aparticular wireless communication device included within a set ofwireless terminals in said wireless communication system; wherein saidset of wireless communication devices includes a plurality of wirelesscommunication devices; wherein said quick page message is for directingsaid set of wireless communication devices to monitor said secondchannel for said full page message; wherein said full page messageidentifies said particular wireless communication device among said setof wireless communication devices; wherein said receiving said quickpage message is during a first time slot assigned to the set of wirelesscommunication devices; wherein said receiving said full page message isduring a second time slot assigned to the set of wireless communicationdevices; wherein said second time slot is assigned to said first timeslot by way of having a time delay calculated by the wirelesscommunication device between said first and second time slots; whereinsaid second time slot occurs after said first time slot.
 11. The methodas set forth in claim 10 wherein said quick page message is comprised ofa single bit of data.
 12. An apparatus for receiving a page at awireless communication device in a wireless telecommunications system,comprising: means for receiving a quick page message via a first, lessencoded channel, said quick page message notifying the wirelesscommunication device to begin monitoring a second channel for a fullpage message; means for receiving said full page message via saidsecond, highly encoded channel; wherein said means for receiving saidfull page message includes processing means for decoding through adecoding system, means for deinterleaving through a deinterleaver, andmeans for processing through a cyclical redundancy check circuit,wherein said quick page message contains less data bits than said fullpage message, such that the amount of processing to process said quickpage message is substantially less than for the full page message in thewireless communication device; wherein said wireless communicationdevice is a particular wireless communication device included within aset of wireless communication devices in said wireless communicationsystem; wherein said set of wireless communication devices includes aplurality of wireless communication devices; wherein said quick pagemessage is for directing said set of wireless communication devices tomonitor said second channel for said full page message; wherein saidquick page message lacks any information for identifying any wirelesscommunication device among said set of wireless communication devices;wherein said full page message identifies said particular wirelesscommunication device among said set of wireless communication devices;wherein said receiving said quick page message is during a first timeslot assigned to the set of wireless communication devices; wherein saidreceiving said full page message is during a second time slot assignedto the set of wireless communication devices; wherein said second timeslot is assigned to said first time slot by way of having a time delaycalculated by the wireless communication device between said first andsecond time slots; wherein said second time slot occurs after said firsttime slot.
 13. The apparatus as set forth in claim 12 wherein said quickpage message is comprised of a single bit of data.
 14. A wirelesscommunication device, comprising: at least one processor configured toreceive a quick page message via a first, less encoded channel, saidquick page message notifying the wireless communication device to beginmonitoring a second channel for a full page message, and receive saidfull page message via said second, highly encoded channel; and a memorycoupled to the at least one processor; wherein said quick page messagecontains less data bits than said full page message, such that theamount of processing to process said quick page message is substantiallyless than for the full page message in the wireless communicationdevice; wherein said wireless communication device is a particularwireless communication device included within a set of wirelesscommunication devices in said wireless communication system; whereinsaid set of wireless communication devices includes a plurality ofwireless communication devices; wherein said quick page message is fordirecting said set of wireless communication devices to monitor saidsecond channel for said full page message; wherein said quick pagemessage lacks any information for identifying any wireless communicationdevice among said set of wireless communication devices; wherein saidfull page message identifies said particular wireless communicationdevice among said set of wireless communication devices; wherein saidreceive said quick page message is during a first time slot assigned tothe set of wireless communication devices; wherein said receive saidfull page message is during a second time slot assigned to the set ofwireless communication devices; wherein said second time slot isassigned to said first time slot by way of having a time delaycalculated by the wireless communication device between said first andsecond time slots; wherein said second time slot occurs after said firsttime slot.
 15. The wireless communication device as set forth in claim14 wherein said quick page message is comprised of a single bit of data.16. An apparatus for paging a wireless communication device in awireless telecommunications system comprising: means for transmitting aquick page message via a first, less encoded channel, said quick pagemessage notifying the wireless communication device to begin monitoringa second highly encoded channel for a full page message; means fortransmitting said full page message via said second channel; whereinprocessing said second channel includes encoding through a encoder,interleaving through an interleaver, and adding cyclic redundancy checkthrough a cyclic redundancy check circuit to said full page message,wherein said quick page message contains less data bits than said fullpage message, such that the amount of processing to process said quickpage message is substantially less than for the full page message in thewireless communication device; wherein said wireless communicationdevice is a particular wireless communication device included within aset of wireless communication devices in said wireless communicationsystem; wherein said set of wireless communication devices includes aplurality of wireless communication devices; wherein said quick pagemessage is for directing said set of wireless communication devices tomonitor said second channel for said full page message; wherein saidfull page message identifies said particular wireless communicationdevice among said set of wireless communication devices; wherein saidtransmitting said quick page message is during a first time slotassigned to the set of wireless communication devices; wherein saidtransmitting said full page message is during a second time slotassigned to the set of wireless communication devices; wherein saidsecond time slot is assigned to said first time slot by way of having atime delay calculated by the wireless communication device between saidfirst and second time slots; wherein said second time slot occurs aftersaid first time slot.
 17. The apparatus as set forth in claim 16 whereinsaid quick page message is comprised of a single bit of data.
 18. Theapparatus as set forth in claim 16 wherein said first channel isestablished via direct sequence modulation with a first channel code,and said second channel is established via direct sequence modulationwith a second channel code.
 19. The apparatus as set forth in claim 16for paging a wireless communication device further comprising: means forgenerating a quick page message before said step of transmitting saidquick page message via a first channel; and means for generating a fullpage message before transmitting said full page message via said secondchannel.
 20. The apparatus as set forth in claim 16 further comprising:means for direct sequence spreading said full page message; and meansfor direct sequence spreading said quick page message.
 21. The apparatusas set forth in claim 16 further comprising: means for receiving saidquick page message during said first time slot; means for activatingsignal processing circuitry; and means for receiving said full pagemessage during said second time slot and using said activated signalprocessing circuitry to process said full message.
 22. The apparatus asset forth in claim 21 wherein said signal processing circuitry iscomprised of a trellis decoding system.
 23. The apparatus as set forthin claim 21 wherein said signal processing circuitry is comprised of adeinterleaver.
 24. The apparatus as set forth in claim 21 wherein saidsignal processing circuitry is comprised of a cyclical redundancy checkcircuit.
 25. An apparatus for paging a wireless communication device ina wireless telecommunications system comprising: at least one processorconfigured to transmit a quick page message via a first, less encodedchannel, said quick page message notifying the wireless communicationdevice to begin monitoring a second highly encoded channel for a fullpage message; transmit said full page message via said second channel; amemory coupled to the at least one processor; wherein processing saidsecond channel includes encoding through a encoder, interleaving throughan interleaver, and adding cyclic redundancy check through a cyclicredundancy check circuit to said full page message, wherein said quickpage message contains less data bits than said full page message, suchthat the amount of processing to process said quick page message issubstantially less than for the full page message in the wirelesscommunication device; wherein said wireless communication device is aparticular wireless communication device included within a set ofwireless communication devices in said wireless communication system;wherein said set of wireless communication devices includes a pluralityof wireless communication devices; wherein said quick page message isfor directing said set of wireless communication devices to monitor saidsecond channel for said full page message; wherein said full pagemessage identifies said particular wireless communication device amongsaid set of wireless communication devices; wherein said transmit saidquick page message is during a first time slot assigned to the set ofwireless communication devices; wherein said transmit said full pagemessage is during a second time slot assigned to the set of wirelesscommunication devices; wherein said second time slot is assigned to saidfirst time slot by way of having a time delay calculated by the wirelesscommunication device between said first and second time slots; whereinsaid second time slot occurs after said first time slot.
 26. Theapparatus as set forth in claim 25 wherein said quick page message iscomprised of a single bit of data.
 27. The apparatus as set forth inclaim 25 wherein said first channel is established via direct sequencemodulation with a first channel code, and said second channel isestablished via direct sequence modulation with a second channel code.28. The apparatus as set forth in claim 25 for paging a wirelesscommunication device wherein said processor is further configured to:generate a quick page message before said step of transmitting saidquick page message via a first channel; and generate a full page messagebefore transmitting said full page message via said second channel. 29.The apparatus as set forth in claim 25 wherein said processor is furtherconfigured to: direct sequence spread said full page message; and directsequence spread said quick page message.
 30. The apparatus as set forthin claim 25 wherein said processor is further configured to: receivesaid quick page message during said first time slot; activate signalprocessing circuitry; and receive said full page message during saidsecond time slot and using said activated signal processing circuitry toprocess said full message.
 31. The apparatus as set forth in claim 30wherein said signal processing circuitry is comprised of a trellisdecoding system.
 32. The apparatus as set forth in claim 30 wherein saidsignal processing circuitry is comprised of a deinterleaver.
 33. Theapparatus as set forth in claim 30 wherein said signal processingcircuitry is comprised of a cyclical redundancy check circuit.